How to do this question?

Note that the parametrisation of catenoid is X(u,v)=(cosh(u)*cos(v), cosh(u)*sin(v), u)

5 Let S be the catenoid of Q49, and r(t) be the curve X(t,t) on S. a. Find the area of the curvilinear triangle PQR on S bounded by the curve r for 0tb, the parametric curve u=0 for 0vb and the curve v=b for 0ub b. Calculate the geodesic curvature of the curve r and show that the other two sides of the triangle PQR are geodesics. Hence find the total geodesic curvature around the boundary of PQR. c. Calculate the total Gaussian curvature inside PQR by integration. d. Verify that part b and c are consistent with the Gauss-Bonnet theorem. 5 Let S be the catenoid of Q49, and r(t) be the curve X(t,t) on S. a. Find the area of the curvilinear triangle PQR on S bounded by the curve r for 0tb, the parametric curve u=0 for 0vb and the curve v=b for 0ub b. Calculate the geodesic curvature of the curve r and show that the other two sides of the triangle PQR are geodesics. Hence find the total geodesic curvature around the boundary of PQR. c. Calculate the total Gaussian curvature inside PQR by integration. d. Verify that part b and c are consistent with the Gauss-Bonnet theorem